Tos-PEG-CH2CO2tBu contains a tosyl (p-toluenesulfonyl) group and a t-butyl ester group.
The tosyl group is known for its ability to protect other functional groups from unwanted reactions. This is achieved by attaching the tosyl group to the functional group, which prevents it from reacting until the tosyl group is removed. In the case of Tos-PEG-CH2CO2tBu, the tosyl group protects the carboxylic acid functional group, which is important for conjugation reactions.
The t-butyl ester group is also important for conjugation reactions, as it can be easily removed under mild conditions to expose the carboxylic acid functional group. This allows for the conjugation of various molecules, such as drugs or imaging agents, to the PEG chain.
Tos-PEG-CH2CO2tBu has been extensively used in the development of drug delivery systems, such as antibody-drug conjugates and imaging agents. Its unique chemical properties allow for the selective conjugation of therapeutic agents to the PEG chain, leading to enhanced stability, solubility, and targeted delivery.